New guidelines urge easy tests to diagnose kidney disease in millions who don't know organs are dying

WASHINGTON (AP) _ Almost 20 million adult Americans have chronic kidney disease, and most don't know it, says new research by the National Kidney Foundation. Another 20 million are at high risk of

Tuesday, February 5th 2002, 12:00 am

By: News On 6

WASHINGTON (AP) _ Almost 20 million adult Americans have chronic kidney disease, and most don't know it, says new research by the National Kidney Foundation. Another 20 million are at high risk of getting it.

Yet early diagnosis and treatment can slow progression of the often fatal disease, which usually displays no serious symptoms until the kidneys have suffered severe damage.

In the face of such facts, the foundation assembled a panel of kidney experts to determine how to catch the disease earlier and offer therapies that can help preserve patients' organs. The key: People at risk need easy urine and blood tests, say the new guidelines, published in this month's American Journal of Kidney Diseases.

``Our goal is to slow the rate of kidney disease worsening so people can live a long time'' without dialysis or kidney transplants, Dr. Andrew Levey, chief of nephrology at Tufts-New England Medical Center in Boston, said Monday.

The kidneys remove waste from the bloodstream. With chronic kidney disease, the organs slowly lose that filtering ability and eventually become so damaged that a patient dies without dialysis or a kidney transplant. Specialists have long warned that end-stage kidney failure is increasing by 2 percent a year in the United States. Already, 300,000 Americans are on dialysis, and 80,000 are living with transplanted kidneys.

But nobody had a precise count of how many people are living with earlier stages of chronic kidney disease or how many were at increased risk of getting it. New government statistics allowed the National Kidney Foundation to do those counts, and the survey concluded that some 40 million people either have chronic kidney disease or are at risk of it.

Most at risk are people with diabetes, high blood pressure, family histories of kidney disease and the elderly.

They need tests for signs of impaired kidney function, the new guidelines say:

_People with kidney disease have increased protein in their urine. A simple urine test, done either by a laboratory or in a doctor's office using a special dipstick test that checks specifically for the protein albumin, measures protein levels.

_The second test estimates patients' GFR _ glomerular filtration rate, a medical term for how well the kidneys are filtering. A blood test that measures levels of the body metabolite creatinine allows doctors to estimate that GFR rate.

Four therapies are available to slow kidney damage:

_Drugs called angiotensin II receptor blockers can slow kidney failure by about two years in people with advanced disease, and proponents expect they'll work even better if taken by people in earlier stages of chronic renal disease. They work by relaxing delicate blood vessels in the kidneys, and are similar to a type of blood pressure medicine called ACE inhibitors.

_Strict blood pressure control is crucial.

_In diabetics, strict blood sugar control protects the kidneys.

_Low-protein diets often are recommended, too, although studies of whether they help have had mixed results, Levey said.

To track how well therapy is working, patients need the blood and urine tests repeated at least yearly, more often once the GFR drops below 60, which separates mild disease from more serious organ damage, Levey said.

For people whose first tests show they don't yet have kidney disease, the foundation still is studying how often screening should be offered.

The American Diabetes Association recommends yearly urine tests for most diabetics. Doctors should not use regular dipstick tests, the kind often used for pregnant women, but the albumin-specific kind or send the urine to a lab to be sure they detect small protein levels, cautioned ADA's Dr. Nathaniel Clark.